This invention relates in general to MicroElectroMechanical Systems, and in particular, to a manifold for distributing a fluid to and from a microvalve.
MicroElectroMechanical Systems (MEMS) is a class of systems that are physically small, having features with sizes in the micrometer range. These systems have both electrical and mechanical components. The term xe2x80x9cmicromachiningxe2x80x9d is commonly understood to mean the production of three-dimensional structures and moving parts of MEMS devices. MEMS originally used modified integrated circuit (computer chip) fabrication techniques (such as chemical etching) and materials (such as silicon semiconductor material) to micromachine these very small mechanical devices. Today there are many more micromachining techniques and materials available. The term xe2x80x9cmicrovalve devicexe2x80x9d as used in this application means a complete, functioning valve having features with sizes in the micrometer range, and thus is by definition at least partially formed by micromachining. Furthermore, a xe2x80x9cmicrovalve devicexe2x80x9d, as used in this application includes a microvalve, and may include other components such as a fluid distributing manifold, pressure, temperature, flow or other types of sensors, pumps or other valves of various types. It should be noted that if components other than a microvalve are included in the microvalve device, these other components may be micromachined components or standard sized (larger) components.
Various microvalve devices have been proposed for controlling fluid flow within a fluid circuit. A typical microvalve device includes a displaceable member or valve movably supported by a body. Depending on the type of valve, the valve may be operatively coupled to an actuator for movement between a closed position and a fully open position. When placed in the closed position, the valve blocks or closes a first fluid port that is placed in fluid communication with a second fluid port, thereby preventing fluid from flowing between the fluid ports. When the valve moves from the closed position to the fully open position, fluid is increasingly allowed to flow between the fluid ports.
A manifold can be used to provide an interconnection between the physically minute and normally closely spaced ports of a microvalve and associated macro sized fluid conduits of the system in which the microvalve is installed.
On a macro scale, it is known to individually laminated assemblies, such as valve manifolds, from uniquely styled stamped laminations. Stamped laminations are stacked to the desired thickness and are held together by a variety of welding methods or with pins or bushings. During the set-up process copper rings or slugs are added at pre-determined locations. In a brazing process, the copper liquefies and flows into all joints forming a strong iron-copper alloy bond that is the heart of the process. All the components are bonded into a single unit having strength often greater than one-piece construction. Such a process is performed by HI TecMetal Group of Cleveland, Ohio.
Also on a macro scale, U.S. Pat. No. 3,747,628 to Holster et al. describes making a fluidic function module for use in a system for constructing fluidic logical and/or analog circuits. The module includes a basic part that comprises three plates and a hood that may be made, for example, of a suitable synthetic material by injection molding. Clamped between them are three diaphragms that provide airtight seals. The plate is provided with an annular valve seat that cooperates with a disc-shaped valve made of a resilient material. In its lower position shown in the drawing the valve cooperates with the annular valve seat, but in its upper position it is capable of cooperating with a valve seat in the plate. The diaphragm through an annular part of smaller thickness is integral with a movable part that has a specially shaped cross-section, the part being referred to as the movable part of the circuit element. A fluidic function module consists of a basic part, a gasket, and a connecting part in the form of a xe2x80x9cuniversal connecting platexe2x80x9d. The universal connecting plate is made of a synthetic material, for example by injection molding, so that the product may simply be manufactured by mass production methods. The universal function connecting plate is provided in both of it""s surfaces with grooves and bores which together form a standard passage system. When the basic part is assembled with the gasket and the universal connecting plate, the combination forms a fluidic module for constructing fluidic circuits which, depending upon the intended use, comprise one or more fluidic modules for performing logical analog and/or combined operations, the function module comprising at least firstly a basic part accommodating a plurality of individual fluidic circuit elements and secondly a function connecting part in the form of the universal connecting plate in which passages have been formed which interconnect the various input, output, air supply and vent passages of the individual circuit elements of the basic part in the appropriate manner, so that the assembly of basic part and connecting part forms a function module which may have, for example, an AND, an OR, a universal or a storage function. Adapting the universal function connecting plate to an intended function of a function module is achieved by removing readily removable partitions of the function connecting plate from between specific passages of the standard passage system on opposite sides of the universal function connecting plate. The partitions are removed by drilling between the passages.
The invention relates to a manifold for distributing a fluid. The manifold can be used to distribute a fluid to and from a microvalve. The manifold includes a first plate having a groove formed in one face thereof. A second plate is fixed to the first plate so as to cover the groove to form a fluid passage through the groove. First and second bores are formed through at least one of the first plate and the second plate to form an inlet and an outlet, respectively, of the fluid passage. Preferably, the face of the first plate or the second plate opposite the face with the grooves formed therein has a solderable pad formed on at least a portion thereof. According to a method of manufacturing, etching the first plate forms the groove. Preferably, an etching process also forms the first and second bores. Also, preferably, the first plate is one of a plurality of plates formed from a single sheet of material. Preferably the sheet of material is a standard sized sheet with locating indicia enabling assembly of the manifold with standard pick and place equipment. Specifically, a method of assembling the manifold includes forming a plurality of first plates from a single sheet; a plurality of second plates from a second sheet; applying a braze material to selected portions of one of the first and second sheets; clamping the sheets together with each of the first plates aligned with a corresponding one of the second plates; heating the first and second sheets, and braze material therebetween, to braze each of the first plates to the corresponding one of the second plates to form a manifold; detaching each manifold from the first and second sheets; and assembling the manifold to a fluid circuit. Optionally, a microvalve is attached to each manifold before the manifold is detached from the first and second sheets.
Various other objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings.